72 



NATURE 



[May 20, 1880 



especially in the great development of its ridges, was also shown 

 to resemble the same bone in the Monotremes. The ungual 

 phalanges were described as broad and obtuse, probably con- 

 structed to bear claws adapted for digging, as in EchiJiia ; the 

 femur also resembles that of the last-named animal. The author 

 remarked upon these approximations to the monotrematous 

 mammalia, in allusion to « hich he proposed the name of Plaly- 

 '•oJosaurus robustus for this animal, the humerus of which was 

 loi inches long and nearly 6 inches broad at the distal end. He 

 .ilso alluded to the interesting problems opened up by the study 

 of these South-African reptiles in connection with their pos4ble 

 relationships to the low implacental mammalia of New Guinea, 

 Australia, and Tasmania. — Note on the occurrence of a new 

 species of Igitanodon in the Kimmeridge clay at Cumnor Ilurst, 

 three miles west of Oxford, by Prof. J. Prestwich, F.R.S. The 

 pit in which the occurrence of Igiianodoii was discovered was 

 worked in Kimmeridge clay at the foot of an outlying mass of 

 Lower Greensand forming an isolated hill. The Portland beds, 

 which occur at Shotover, are here wanting. The bones were 

 found in a thin sandy seam intercalated in the clay, and tra- 

 versing the hill at least fifteen feet below the greensand. The 

 skeleton was probably almost entire ; but, as attention was not 

 directed to it until nearly all the clay had been removed, many 

 bones were \oA and others injured. Several vertebra; ailchthyo- 

 smirus w ere found in the ■■ same seam, and the characteristic 

 Giyp/um zirgida occurred in profusion. The cl.ay above and 

 below contained fossils of Kimmeridge types. The author stated 

 his opinion that land probably lay to the south-west of the 

 Oxford district. — On Iguanodon fresiwichii, a new species from 

 the Kimmeridge clay, by J. W. Hulke, F.R.S. In this paper 

 the author described in detail the remains of Iguanodon found at 

 Cumnor Hurst in the Kimmeridge clay, as described in the pre- 

 ceding paper. They illustrated nearly every part of the skeleton 

 of an immature individual, adding greatly to our knowledge of 

 the variation of the vertebra; in the several regions of the 

 vertebral column, and of the structure of the head and hind 

 limbs. In the latter both the tibia and the fibula articulate (as 

 in embryo birds) with the os calcis, which bone is now first 

 identified in Ignanodon. The sacral vertebrae were only four in 

 number, and the species further diftered from the Wealden 

 Ignanodon manieUi in the simpler character of the serration of 

 the teeth, of which the lamellae are not mammillated, and in 

 having the vertebrae of the trunk and sacrum not so compressed. 

 The author named the species Igtianodon prcstwichii. 



Institution of Civil Engineers, May 11. — Mr. W. H. 

 Barlow, F.R.S., president, in the chair.— On the manufacture 

 and testing of Portland cement, by Major-General H. V. D. 

 Scott, F.R.S., and Mr. Gilbert R. Redgrave.— On Portland 

 cement concrete, and some of its applications, by Mr. E. A. 

 Bernays. — On Portland cement: its nature, tests, and uses, by 

 Mr. John Grant. 



Anthropological Institute, May 11. — A. L. Lewis in the 

 chair. — The following papers were read :— Notes on prehistoric 

 discoveries in Central Russia, by C. H. E. Carmichael, M.A. — 

 Notes on the occurrence of stone implements of the surface- 

 period in South Russia, by W. D. Gooch.— Notes on the 

 Western Regions, by A. WyUe. — On jade implements in 

 Switzerland, by Hodder ^L Westropp. — Flint implements from 

 the Valley of the Banu, by W. J. Knowles. 

 Paris 



Academy of Sciences, May 10. — M. Edm. Eecquerel in the 

 chair.— The following papers were read :— On the transcendants 

 which play a fundamental part in the theory of planetary per- 

 turbations, by M. Tisserand.— On a proposition of the theory of 

 elliptic functions, by M. Hermite. — On a rain of dust observed 

 from April 21 to 25, 1S80, in the departments of Basses-Alpes, 

 Isere, and Ain, by M. Daubree. This dust gave a reddish 

 tinge to snow on the mountains at Barcelonnette, up to 2,800 

 and 3,000 m. (snow further up remaining white). Its chief 

 mineralogical characters were : effervescence with acids, mixture 

 of hydrated peroxide of iron, presence of spangles of mica, 

 residue of fusible acids, principally feldspathic. The dust is 

 thought to be of terrestrial origin, but not volcanic, nor Saharan. 

 (Somewhat similar showers fell in France in October, 1846, and 

 Jlay, 1863.) The same phenomenon seems (from another note) 

 to have been experienced at Autun (Saone-et-Loire) on April 15, 

 i.e., ten days before.— On the crystaUine form of magnesium, by 

 M. Des Cloizeaux. Having examined the fine magnesium 

 crystals lately obtained by M. Dumas, he finds that among the 

 rhombohedric metals magnesium is that which, after zinc, pre- 



sents the most acute primitive rhombohedron. The crystals in 

 question are very malleable and sectile ; no cleavage was ob- 

 served. — On a Cicadella {Hysteropterum aptcrum) which attacks 

 the vines in the department of the Gironde, by M. Blanchard. — 

 On the law of reciprocity in the theory of numbers, by Prof. 

 Sylvester. — On the new siphon established over the Canal .Saint 

 RIartin, and on the works of sanitation of the Bercy quarter, by 

 M. Levy. The sewers of Bercy (which formerly discharged into 

 the Seine) are in some parts lower than the collector designed 

 for them, and had to cross the Canal Saint Martin to reach this. 

 An ingenious system of siphons and trompes was devised to 

 meet the difiiculty. — On linear functions, by M. Pellet. — Ex- 

 perimental researches on the decomposition of some explosives ; 

 analysis of products, by MM. Sarran and Vieille. This related 

 to decomposition of explosives under a pressure near the atmo- 

 spheric. In this case all the explosives liberate bioxide of nitro- 

 gen and carbonic oxide. It is important, then, in mining 

 operations to avoid with all care failure of detonation. — On the 

 determination of algebraic integrals of algebraic differentials, by 

 M. Zeuthen. — On simultaneous linear equations and on a class 

 of non-plane cui"ves, by M. Picard. — On a class of functions of 

 two independent variables, by M. Picard. — On the theory of 

 phenomena of interference where rotatory polarisation inter- 

 venes, by M. Gouy. He takes a point of view of interference 

 phenomena different from that of Fresnel, and superior in sim- 

 plicity. — On the equipotential lines of a plane formed of two 

 halves unequally conductive, by M. Guebhard. — On the mutual 

 actions of magnetic needles plunged in liquids, by M. Obalski. 

 Two magnetic needles are hung opposite each other (and a little 

 beyond the range of attraction) by two unlike poles from very 

 fine threads over water in a vessel, which water can be raised 

 gradually over them (by means of a connected tube of caoutchouc). 

 When immersion begins, the needles draw near each other by 

 their immersed parts, and wlien the immersion has reached the 

 third or fourth of the needles' length, they go together. This is 

 probably due to the separating force of gravity being weakened 

 by immersion. — Analysis by the graphic method of movements 

 produced by excitations of the brain, by MM. Francois Franck 

 and Pitres. To the detached tendon of a limb muscle they 

 attached the transmitting myograph ; an electro-magnetic signal 

 (of M. Deprez) registered the time on the drum, and another 

 signal the excitation. The character of movements caused by 

 various electrical excitations is described. As to retardation of 

 the movement on the instant of cortical excitation, this is found 

 constant for a given muscular group in the same animal, whatever 

 the form or intensity of the electric excitant. A notable part of 

 it is due to physiological resistance of the grey cortical substance. 

 Beyond a certain intensity of stimulation movements are pro- 

 duced on the same side of the body as the part of brain stimu- 

 lated, as well as on the opposite, and the retardation for these 

 movements is greater. The retardation is gi-eater for hind than 

 for fore limbs. — On a rain of dust at Autun, by M. De Jussieu 

 (see above). — M. De Lesseps presented specimens of silver ore 

 from California, and gave some information about Mr. ilackay's 

 mines at Virginia City, the galleries of which have been pushed 

 about 1,000 metres, a depth hardly exceeded in Europe (Bohemia). 

 Descent is by means of hydraulic motors. 



CONTENTS Pagb 



The Science of Laxguage. By A. H. Keane 49 



Statics 52 



Australian Orchids 53 



Letters to the Editor : — 



Ice Crystals.— John Le Conte 34 



Anchor-Ice. — J. Rae 54 



" Sarsens."— A. G. Renshaw 55 



An Entomostracon Living in Tree-Tops (With I ItustratioiC) . . ss 

 (JN THE Physical Aspects of the Vortex-Ato.\i Theory. By S. 



ToLVER Preston .A c' ' ' ^^ 



Comparative Anatomy OF Man, I. By Prof. Flower, F.R.S. . . .59 



Variations fro.m Mariotte's Law (With lUiistratioiis) .... 61 



Notes ^+ 



ouk astro.nomical colvmn :— 



The Transit of Mercury, May S-6, 1878 07 



The Second Comet of 1880 (Schaberle, April 6) 67 



Prof. C. A. F. Peters 67 



Geographical Notes ■ . * • • ^7 



The Parallel Roads of Lochaber— the Problem and its\ arious 



Solutions. By William Jolly, F.R.S. E 68 



University AND Educational Intelligence 70 



Scientific Serials 7° 



Societies and Academies 7° 



Errata.-VoI. xxi. p. 202, col. 2. line 5 from bottom, fur " Lethu" read 

 " Petho " ; p, 220, col. 2, line 22 from bottom, for " Letho read Petho. 



